This invention is concerned with the improvement of a pneumatically driven nut running tool, such as an impact wrench, with directional torque selector mechanism which enables the operator to effect a change in the torque output value of the tool to suit the needs of the intended direction of tool operation.
A tool of this improved nature is especially desirable for wheel work in auto service stations in applying or removing fasteners such as lug bolts or nuts, as well as in other applications.
The full torque capacity of the tool is often required to remove overtightened or frozen lug bolts; whereas a lesser torque is desired to be applied to avoid overtightness and possible damage when installing the bolts. The direction in which this full or lesser torque is to be applied is determined according to whether the particular bolts have right or left hand threads.
The general objective of the present invention is to provide a pneumatically driven nut running tool which enables the operator to select a torque as needed according to the intended direction of operation of the tool for removing or installing a threaded fastener. This selected torque may be either of a predetermined limited value or of full value.
In accordance with the invention, there is provided a pneumatically powered nut running tool comprising an air driven torque transmitting reversible motor, a throttle valve for admitting supply air to the tool to drive the motor, a reversible valve selectively manipulative to guide air from the throttle valve to drive the motor in either a forward or reverse direction; and pressure air regulator means manipulative to a first position for conducting air from the reverse valve at full pressure to the motor, and manipulative to a second position for causing air from the reverse valve to flow at a regulated predetermined reduced pressure to the motor.